Chlamydophila infection is known as an occupational hazard to veterinarians, farmers, poultry workers. Serum levels of the soluble Intercellular Adhesion Molecule-1 (sICAM-1), is associated with C. seropositivity. Since no data about ICAM-1 levels and C. psittaci infection are known, the aim of this work was to assess if chronic persistent C. psittaci infection constantly stimulates the expression of sICAM-1, independent of the characteristic symptoms of ornithosis. C. psittaci seropositivity and serum concentrations of sICAM-1 were investigated in 30 farmers and 20 age-matched healthy public employees as controls. Increased serum sICAM-1 levels were found in the group of farmers exposed to infectious risk compared to controls, and the serum concentrations of sICAM-1 was significantly correlated with a high IgG titre against C. psittaci. It is therefore possible to suggest a sICAM-1 measurement for use as a tool to verify the development of C. psittaci chronic infection in an occupational setting.